Tamper resistant immediate release capsule formulation comprising tapentadol

ABSTRACT

The invention is directed to an immediate release capsule which mitigates the abuse of Tapentadol or physiologically acceptable salt thereof by direct intravenous injection. The capsule comprises a tamper resistant formulation which when mixed with water and heated, results in a turbid, bubbling mixture that is not injectable with a standard insulin syringe.

This application claims priority of European patent applications EP 14 167 923.3, filed on May 12, 2014, and EP 14 176 277.3, filed on Jul. 9, 2014, the entire contents of which patent applications are incorporated herein by reference.

The invention relates generally to an immediate release capsule formulation that is resistant to parenteral abuse of Tapentadol or a physiologically acceptable salt thereof.

Many active pharmaceutical ingredients, in addition to having an excellent activity in their appropriate application, also have potential for abuse, i.e. they can be used by an abuser to bring about effects other than those intended. For example, opioid analgesics, which are highly active in combating severe to very severe pain, are frequently used by abusers to induce a state of narcosis or euphoria. Typically, a particular dose of an opioid analgesic is more potent when administered parenterally as compared to the same dose administered orally. One popular mode of abuse of oral opioid formulations involves the extraction of the opioid from the dosage form, and the subsequent injection of the opioid (using any suitable vehicle for injection such as an insulin syringe) in order to achieve a “high”.

This abuse problem is well known to the pharmaceutical and medical industries. Various methods of obviating such abuse have been devised.

GB 2 238 478 is directed to a pharmaceutical unit dosage form which comprises a soft gelatin capsule shell or a two-piece hard gelatin capsule filled with a benzodiazepine in a gel comprising at least 63% of polyethylene glycol 600, at least 4% by weight of polyethylene glycol 4000 or 6000 and at least 21% by weight of an intermediate polyethylene glycol. This purports to solve the abuse problem by using a formulation that is too viscous to be expelled from a syringe.

U.S. Pat. No. 7,230,005 is directed to solving the abuse problem discussed above by converting the active pharmaceutical ingredient to a poorly absorbed ester pro drug or other prodrug derivative prior to formulation. Mechanical processing of tablet or caplets containing the prodrug does not release the active API. The tablets and capsule beads containing prodrugs or other drugs can be formulated with a sufficient amount of a thickening agent to impede inappropriate intravenous administration of formulations that are not indicated for these modes of administration.

U.S. Pat. No. 7,399,488 is directed to an abuse-deterrent pharmaceutical composition wherein a drug is modified to increase its lipophilicity. In preferred embodiments the modified drug is homogeneously dispersed within microparticles composed of a material that is either slowly soluble or not soluble in water. In some embodiments the drug containing microparticles or drug particles are water insoluble, but enzymatically degradable by enzymes present in the human gastrointestinal tract.

U.S. Pat. No. 7,510,726 relates to an abuse deterrent dosage form of opioids, wherein an analgesically effective amount of opioid analgesic is combined with a polymer to form a matrix. The formation of a high-viscosity gel is a result of exposing the solid dosage form to water.

U.S. Pat. No. 7,776,314 relates to a solid administration form, protected from parenteral abuse and containing at least one viscosity-increasing agent in addition to one or more active substances that have parenteral abuse potential. The agent forms, when a necessary minimum amount of an aqueous liquid is added, on the basis of an extract obtained from the administration form, a preferably injectable gel that remains visually distinct when introduced into another quantity of an aqueous liquid.

U.S. Pat. No. 7,842,307 discloses oral dosage form comprising a therapeutically effective amount of an opioid analgesic, an opioid antagonist and one or more physiologically acceptable excipients. The dosage form further includes a gelling agent in an effective amount to impart a viscosity unsuitable for administration selected from the group consisting of parenteral and nasal administration to a solubilized mixture formed when the dosage form is crushed and mixed with from about 0.5 to about 10 ml of an aqueous liquid. The active pharmaceutical ingredient active pharmaceutical ingredient that is suspended in high viscosity solutions is unsuitable for abuse via intravenous injections.

U.S. Pat. No. 8,202,542 discloses a modified release tablet formulation of an opioid drug bound to an ion exchange resin, coated with a hybrid coating comprising a barrier coating containing a polyvinyl acetate polymer and a plasticizer and an enteric polymer mixed therewith.

U.S. 2005/152843 relates to a solid administration form, protected from parenteral abuse and containing at least one viscosity-increasing agent in addition to one or more active substances that have parenteral abuse potential. The agent forms, when a necessary minimum amount of an aqueous liquid is added, on the basis of an extract obtained from the administration form, a preferably injectable gel that remains visually distinct when introduced into another quantity of an aqueous liquid.

U.S. 2008/152595 relates to an abuse deterrent formulation of an oral dosage form of a therapeutically effective amount of any active drug substance that can be subject to abuse combined with a gel forming polymer, a nasal mucosal irritating surfactant and a flushing agent. Such a dosage form is intended to deter abuse of the active drug substance via injection, nasal inhalation or consumption of quantities of the dosage unit exceeding the usual therapeutically effective dose.

U.S. 2008/280975 discloses methods for preventing or minimizing the intensity of the serotonin syndrome in humans and lower animals which comprises administering proserotonergic agents and serotonin surge protectors.

U.S. 2009/0215808 is directed to oral pharmaceutical composition that is abuse-resistant, and its use to deliver the active pharmaceutical ingredient.

U.S. 2010/0099696 is directed to an oral dosage formulation containing a therapeutically effective amount of a drug susceptible to abuse and an effective amount of an embolizing agent which causes the production of a solid or semi-solid embolus or blockage alter tampering. The embolizing agent is a pH dependent polymer such as methacrylate, cellulose based polymer, and phthalate.

U.S. 2010/0249045 is directed to tamper resistant pharmaceutical compositions of opioids and extended release pharmaceutical compositions. All of the formulations appear to be for caplets.

EP 1 611 880 is directed to overcoming the abuse problem by providing pharmaceutical compositions of drugs known as replacement narcotics used in drug addiction therapy, such as methadone and/or its salts, preferably its hydrochloride, in a uniform soft-gel matrix to be taken orally without chewing, whereby the uniform matrix has the shape and size of a pill or capsule of a certain formulation. The formulation is entirely gelatinized, i.e., uniformly incorporated within the soft-gel matrix.

WO 2010/044842 is directed to solving the abuse problem by including an effective amount of embolizing agent (i.e., coagulating agent) which causes the production of a solid or semi-solid embolus or blockage alter tampering. Suitable examples of embolic agents are thrombin, cellulose diacetate polymer, albumin, gelatin, fibrinogen, 5 lactoglobulin, immunoglobulin, actin, acrylamide, polyacrylonitrile, polyurethane, polyvinylacetate, nitrocellulose and copolymers of urethane/carbonate and copolymers of styrene/maleic acid and pH sensitive polymers consisting of copolymers of methyl and butyl methacrylate and dimethylaminoethylmethacrylates.

WO 2010/066034 is directed to novel narcotic formulations having a decreased injection abuse potential. An oral pharmaceutical formulation is provided that makes the extraction of the active pharmaceutical ingredient more difficult, in particular in aqueous and alcohol solvents, and therefore prevents, or at least significantly reduces, the potential for abuse, while purportedly allowing the pharmaceutical formulation to release the active pharmaceutical ingredient in the gastrointestinal tract upon ingestion to allow for the desired pharmacological effect. The drug formulation is in form of a tablet, comprising a salt of the pharmaceutical active ingredient, and an alkalizing agent for reducing the solubility of the drug in no-acidic solutions.

WO 2010/105672 relates to a controlled release pharmaceutical composition, comprising a core, comprising a pharmaceutical active ingredient, whereby the core is coated by an ethanol resistance conferring coating layer which has the effect of conferring the release profile of the pharmaceutical active ingredient to be resistant against the influence of ethanol. The carious coating techniques and formulations related thereto are taught.

WO 2011/128630 relates to an oral pharmaceutical composition comprising a physiologically tolerable gelled oil-in-water emulsion containing a drug of abuse.

WO 2013/003845 is directed to oral drug dosage forms designed to reduce the abuse potential of an oral dosage form of an opioid analgesic. The oral drug dosage form comprises a first population of drug-resin complex particles comprising an analgesically effective amount of an opioid drug coated with a water-permeable diffusion barrier coating; and a second population of ion exchange-resin complex particles comprising an aversive agent coated with a polymer coating sufficient to substantially prevent release of the aversive agent under normal use conditions. The abuse problem is addressed by using two different particles within the liquid or solid dosage form.

The abuse problem that the invention overcomes is based on illicitly obtaining the active pharmaceutical ingredient from a dosage form such as a capsule that comprises a capsule filling which in turn comprises the active pharmaceutical ingredient. Many drug abusers are able to separate the capsule filling from the capsule shell and to extract the active pharmaceutical ingredient by further treatment. Such treatment typically includes solubilizing the capsule filling with a small amount of water, such as about 5 mL of water per 1 capsule. This mixture is then heated, optionally boiled, and filtered through a filter, such as a cigarette filter, into a hypodermic syringe. Such a syringe may be an insulin syringe equipped with a needle. The syringes that are used for insulin injections typically comprise 20 to 31 gauge needles.

Typically, due to viscosity challenges, the drug abuser will select a relatively thicker gauge needle such as a 20 gauge needle (about 0.91 mm outer diameter, 0.60 mm inner diameter).

There are many different methods how drug abusers recover the active pharmaceutical ingredients from capsules. Most of these techniques are neither well studied nor documented, due to their illicit nature.

It is an object of the invention to provide a tamper resistant pharmaceutical dosage form containing Tapentadol or a physiologically acceptable salt thereof having advantages compared to the dosage forms of the prior art. In particular, it is an object of the invention to provide a tamper resistant capsule comprising a capsule filling which when mixed with water and heated, results in a turbid, bubbling mixture that is not injectable with a standard insulin syringe.

This object has been achieved by the subject-matter of the patent claims.

A first aspect of the invention relates to a tamper resistant pharmaceutical capsule comprising a capsule filling and a capsule shell, wherein said capsule filling is encapsulated by said capsule shell and wherein said capsule filling comprises

-   (a) Tapentadol or a physiologically acceptable salt thereof in an     amount within the range of from 10 mg to 400 mg, as equivalent     weight relative to Tapentadol free base; and -   (b) a liquid excipient blend comprising a solvent, a surfactant, and     a viscosity enhancer; and     wherein the capsule provides immediate release of Tapentadol or the     physiologically acceptable salt thereof upon oral administration.

The invention is directed to the development of an immediate release capsule formulation. More specifically, the invention is directed to an immediate release capsule formulation, which mitigates the abuse of Tapentadol or physiologically acceptable salt thereof by direct intravenous injection.

The invention addresses any of the above described illicit treatments of capsules that include heating or boiling of the capsule filling or of the capsule or of a dilution of the same, to obtain a mixture comprising Tapentadol or physiologically acceptable salt thereof, which can then be injected.

For illustrative purposes, the principles of the invention are described by referencing various exemplary embodiments. Although certain embodiments of the invention are specifically described herein, one of ordinary skill in the art will readily recognize that the same principles are equally applicable to, and can be employed in other systems and methods. Before explaining the disclosed embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the details of any particular embodiment shown. Additionally, the terminology used herein is for the purpose of description and not of limitation. Furthermore, although certain methods are described with reference to steps that are presented herein in a certain order, in many instances, these steps may be performed in any order as may be appreciated by one skilled in the art; the novel method is therefore not limited to the particular arrangement of steps disclosed herein.

According to a preferred embodiment of the invention, the Tapentadol or physiologically acceptable salt thereof is dissolved or suspended in a self-emulsifying drug delivery system such as a lipophilic self-emulsifying drug delivery system that is not injectable with a standard insulin syringe.

The pharmaceutical capsule according to the invention comprises an outer capsule shell that encapsulates an inner capsule filling (inner core). Typically, the capsule shell completely surrounds the capsule filling so as hold the capsule filling. As the capsule filling comprises a liquid component, namely the liquid excipient blend, the capsule shell inter alia serves the purpose of containing the liquid excipient blend as well as the active pharmaceutical ingredient, namely Tapentadol or a physiologically acceptable salt thereof, and providing the capsule with a rigid outer shape such that is may be orally administered by a patient.

The tamper resistant capsule of the invention comprises the capsule shell and the capsule filling. The “capsule filling” is a liquid or semiliquid fluid that is encapsulated by the capsule shell. The composition of the capsule filling is formulated so that the capsule filling is tamper resistant thereby rendering the entire pharmaceutical capsule tamper resistant.

In a preferred embodiment, the pharmaceutical capsule according to the invention has a total weight within the range of from 200 to 2500 mg, more preferably 300 to 2000 mg, still more preferably 400 to 1800 mg, even more preferably 600 to 1600 mg, most preferably 700 to 1400 mg, and in particular 900 to 1300 mg.

In another preferred embodiment, the pharmaceutical capsule according to the invention has a total weight within the range of from 200 to 2500 mg, more preferably 300 to 2200 mg, still more preferably 700 to 1900 mg, even more preferably 900 to 1700 mg, most preferably 1100 to 1500 mg, and in particular 1200 to 1400 mg.

The parenteral tamper resistant capsule comprises a capsule shell that may comprise any suitable material that is known to form a capsule.

According to a preferred embodiment of the invention, the capsule is a soft capsule, such as a soft gelatin capsule. The shell may be formed from a combination of gelatin, water, and a plasticiser. Additional optional ingredients include an opacifier.

According to another embodiment of the invention, the capsule is a hard gelatin capsule. The hard gelatin capsule comprises two sections, one slipping over the other, thus completely enclosing the capsule filling. The hard gelatin capsule may be formed and filled by the capsule filling in any manner as known in the art. According to a preferred embodiment, the hard gelatin capsule is one that is exclusively designed to optimize liquid filling.

The composition of the capsule shell is such that it is compatible with the capsule filling.

Gelatin is a substantially pure protein food ingredient, obtained by the thermal denaturation of collagen, which is the most common structural material and most common protein in animals. Gelatin forms thermally reversible gels with water, and the gel melting temperature (<35° C.) is below that of human body temperature (37° C.), which gives gelatin products unique properties, such as reversible sol-gel transition states at near physiologic temperatures. Gelatin is an amphoteric protein with an isoionic point between 5 and 9, depending on raw material and method of manufacture. Type A gelatin, with an isoionic point of 7 to 9, is derived from Collagen with acid pretreatment. Type B gelatin, with an isoionic point of 4.8 to 5.2, is the result of alkaline pretreatment of the Collagen.

Examples of plasticizers include propylene glycol, glycerol, glycerin, sorbitol, and Anidrisorb.

Under another embodiment of the invention the shell is composed of a material that does not include gelatin. Exemplary components of non-gelatin capsules include modified starch, modified cellulose, substances derived from seaweed, and carrageenan.

The shell may be composed of substances that meet the ethical, cultural, dietary, or religious restrictions of the target consumer of the capsule. According to a preferred embodiment of the invention, the shell meets the Kosher standards. Under another embodiment of the invention the shell meets the Halal standards.

The pharmaceutical capsule according to the invention is filled with a capsule filling comprising Tapentadol or a physiologically acceptable salt thereof and a liquid excipient blend. The liquid excipient blend comprises a solvent, a surfactant, and a viscosity enhancer and optionally additional physiologically acceptable components so as to solubilize or miscibilize the Tapentadol or the physiologically acceptable salt thereof.

Preferably, the capsule filling consists of the Tapentadol or a physiologically acceptable salt thereof and the liquid excipient blend, i.e. does not contain any additional ingredients.

The mixture of Tapentadol or a physiologically acceptable salt thereof and the liquid excipient blend, i.e. the capsule filling, itself is preferably a liquid or semiliquid fluid. Said mixture may be a solution or dispersion. Dispersions may include suspensions, water in oil emulsions and oil in water emulsions. Solutions and suspensions are preferred. Emulsions (o/w and w/o) are included but less preferred.

In a preferred embodiment, the liquid excipient blend, i.e. the capsule filling, is a solution or a suspension wherein in case of a suspension the liquid phase thereof is preferably a single phase, e.g. is not further divided into an aqueous phase and an oil phase.

In a preferred embodiment, the liquid excipient blend, preferably the capsule filling, does not contain an oil in water emulsion.

In a preferred embodiment, the liquid excipient blend, preferably the capsule filling, does not contain a lipoid, lipid or oil. Thus, the liquid excipient blend, preferably the capsule filling, preferably does not contain a lipid phase or oil phase.

The liquid excipient blend comprises a solvent, a surfactant, and a viscosity enhancer. Optionally, the liquid excipient blend may comprise a plasticizer. Optionally, the liquid excipient blend may comprise an ion exchange resin.

Preferably, the capsule filling contained in the pharmaceutical capsule according to the invention has a total weight within the range of from 50 to 2000 mg, more preferably 100 to 1750 mg, still more preferably 250 to 1500 mg, even more preferably 500 to 1400 mg, most preferably 700 to 1200 mg, and in particular 900 to 1000 mg.

As discussed in the Experimental section below, the 1000 mg of excipients mixture has an excellent correlation to the tamper resistance characteristics of the capsule of capsule filling weight 950 mg. All excipient mixtures, which fulfilled tamper resistance showed good dispersibility, and worked with both amounts 250 and 1000 mg.

The pharmaceutical capsule according to the invention is tamper resistant (abuse resistant, abuse deterrent). For the purpose of the invention, “tamper resistant” means that the Tapentadol or physiologically acceptable salt thereof that is contained in the pharmaceutical capsule according to the invention may not be easily isolated from the pharmaceutical capsule and provided in a form suitable for parenteral administration by an abuser. The degree of tamper resistance is to at least impede parenteral abuse, preferably to make parenteral abuse practically impossible by means of techniques and devices that are typically available to an abuser. Preferably, “tamper resistant” means that it is difficult for an average drug abuser to take the necessary steps to isolate the Tapentadol or physiologically acceptable salt thereof from the capsule to the level necessary to administer the Tapentadol or physiologically acceptable salt thereof parenterally. The degree of difficulty in obtaining the Tapentadol or physiologically acceptable salt thereof ranges from impossibility (0% of the Tapentadol or physiologically acceptable salt thereof is delivered parenterally) to challenging (up to 33% of the Tapentadol or physiologically acceptable salt thereof is delivered parenterally). According to a preferred embodiment of the invention, the tamper resistant capsule filling provides no more than 33% of the Tapentadol or physiologically acceptable salt thereof for parenteral delivery.

The term “parenteral” as used in the phrase “parenteral tamper resistant capsule” means that the Tapentadol or physiologically acceptable salt thereof is introduced into the human body via a parenteral route. The term “parenteral” includes introduction of the Tapentadol or physiologically acceptable salt thereof into the body via an injection. Such injection may be intradermal, subcutaneous, transdermal, intravenous, or intramuscular. According to a preferred embodiment of the invention the term “parenteral” refers to “intravenous”.

To test the tamper resistance, a weighed aliquot corresponding to the amount of capsule filling material is transferred to a metal tablespoon and mixed with 5 mL of purified water to create a mixture. This mixture is stirred with a spatula and then briefly heated to boiling over an open flame. After allowing the mixture to cool for about 1 minute, the mixture may be filtered through a cigarette filter. The filtrate is then aspirated into a 5 mL disposable syringe equipped with a 20 gauge, 25 mm long needle. Alternatively, the aqueous mixture (5 mL purified water) may be boiled and directly aspirated into the 5 mL syringe without prior filtering through a cigarette filter.

There are several different characteristics that may render the pharmaceutical capsule, particularly the capsule filling tamper resistant. One characteristic that renders the capsule filling tamper resistant is that its viscosity increases upon heating or boiling of the formulation in water. The viscosity of the mixture is increased to such a level that it is at least very difficult or even impossible to fill the insulin syringe with the mixture. According to a preferred embodiment of the invention, the viscosity of the heated mixture increases to a level that it may not be deliverable even through needles with the largest diameters commonly used in delivery of insulin.

The second characteristic that may render the pharmaceutical capsule, particularly the capsule filling tamper resistant is that upon heating or boiling the mixture of the capsule filling with water, bubbles occur in the mixture. The presence of such bubbles makes it more difficult to draw the mixture into the syringe. The bubbles also have a deterrent effect in that intravenous drug users tend to avoid introduction of air bubbles into their bloodstream due to their fear about air embolism.

Another aspect of the invention is a capsule comprising a parenteral tamper resistant capsule filling which when mixed with water and heated, results in a mixture which when filtered, the liquid extract preferably comprises at most 33 wt.-%, more preferably at most 25 wt.-%, still more preferably at most 20 wt.-%, even more preferably at most 15 wt.-%, most preferably at most 10 wt.-%, and in particular at most 5 wt.-% of the dosage of Tapentadol or a physiologically acceptable salt thereof originally contained in the pharmaceutical capsule.

Although there are many combinations of the capsule filling components that may work well to deliver the Tapentadol or physiologically acceptable salt thereof upon prescribed oral administration, it has been surprisingly found that only certain combinations of the capsule filling components additionally provide parenteral tamper resistance.

Preferably, the tamper resistant capsule according to the invention comprises a capsule shell and a capsule filling that in turn comprises

-   (a) Tapentadol or a physiologically acceptable salt thereof in an     amount within the range of from 10 mg to 400 mg, as equivalent     weight relative to Tapentadol free base; and -   (b) a liquid excipient blend comprising a solvent, a surfactant, and     a viscosity enhancer, such that a mixture of 250 milligrams of the     liquid excipient blend with 5 milliliters of water at the mixture's     boiling point forms a viscous phase which cannot pass through a 25     millimeter long needle having an inner diameter of 0.60 millimeters;     wherein the capsule provides immediate release of Tapentadol or the     physiologically acceptable salt thereof upon oral administration.

Preferably, the tamper resistant capsule according to the invention comprises a capsule shell and a capsule filling that in turn comprises

-   (a) Tapentadol or a physiologically acceptable salt thereof in an     amount within the range of from 10 mg to 400 mg, as equivalent     weight relative to Tapentadol free base; and -   (b) a liquid excipient blend comprising a solvent, a surfactant, and     a viscosity enhancer, such that a mixture of 250 milligrams to 1000     milligrams of the liquid excipient blend with 5 milliliters of water     at the mixture's boiling point forms a viscous phase which cannot     pass through a 25 millimeter long needle having an inner diameter of     0.60 millimeters;     wherein the capsule provides immediate release of Tapentadol or the     physiologically acceptable salt thereof upon oral administration.

Tapentadol is 3-[(1R,2R)-3-(Dimethylamino)-1-ethyl-2-methylpropyl]phenol having the following general formula:

For the purpose of the specification, “Tapentadol or physiologically acceptable salt thereof” also includes a prodrug. The term “prodrug” means a compound that is a metabolic precursor to Tapentadol or a physiologically acceptable salt thereof. This precursor is transformed in vivo to provide Tapentadol or a physiologically acceptable salt thereof which has the desired therapeutic effect.

For the purpose of the specification, “physiologically acceptable salt” means a salt that is physiologically tolerable and that possesses the desired pharmacological activity of Tapentadol. Such salts include: acid addition salts, formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or formed with organic acids such as acetic acid, propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvic acid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, 3-(4-hydroxybenzoyl)benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, 1,2-ethane-disulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, 4-chlorobenzenesuifonic acid, 2-naphthalenesulfonic acid, 4-toluenesulfonic acid, camphorsulfonic acid, 4-methylbicyclo[2.2.2]-oct-2-ene-1-carboxylic acid, glucoheptonic acid, 3-phenylpropionic acid, trimethylacetic acid, tertiary butylacetic acid, lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylic acid, stearic acid, muconic acid, and the like; and salts formed when an acidic proton present in the parent compound either is replaced by a metal ion, e.g., an alkali metal ion, an alkaline earth ion, or an aluminum ion; or coordinates with an organic Base such as ethanolamine, diethanolamine, triethanolamine, tromethamine, N-methylglucamine, and the like. Tapentadol hydrochloride is preferred.

For the purpose of the specification, “physiologically acceptable” means that which is useful in preparing a pharmaceutical composition that is generally safe, non-toxic, and neither biologically nor otherwise undesirable and includes that which is acceptable for human pharmaceutical use.

Furthermore, in addition to the above compounds, for the purpose of the specification, “Tapentadol or physiologically acceptable salt thereof” also includes a solvate of any of these compounds. The term “solvate” refers to an aggregate that comprises one or more molecules of Tapentadol or physiologically acceptable salt thereof with one or more molecules of a solvent. The solvent may be water, in which case the solvate may be a hydrate. Alternatively, the solvent may be an organic solvent. According to one definition, the term “solvate” refers to the Tapentadol or physiologically acceptable salt thereof in its state prior to the dissolution in the liquid excipient blend. According to another definition, the solid particles of the Tapentadol or physiologically acceptable salt thereof suspended in the liquid excipient blend may comprise a co-precipitated solvent.

The pharmaceutical capsule according to the invention comprises Tapentadol or a physiologically acceptable salt thereof, preferably Tapentadol hydrochloride, in an amount within the range of from 10 mg to 400 mg, as equivalent weight relative to Tapentadol free base. The amount of Tapentadol or a physiologically acceptable salt thereof is expressed as equivalent weight relative to Tapentadol free base. Thus, for example, an amount of 100 mg Tapentadol or a physiologically acceptable salt thereof correspond to about 116.48 mg Tapentadol hydrochloride.

Preferably, the amount of Tapentadol or a physiologically acceptable salt thereof, expressed as equivalent weight relative to Tapentadol free base, is within the range of 25±5 mg, 50±5 mg, 75±5 mg, 100±5 mg, 150±5 mg, 200±5 mg, or 250±5 mg.

Preferably, the total content of Tapentadol or physiologically acceptable salt thereof, as equivalent weight relative to Tapentadol free base, is within the range of from 0.1 to 25 wt.-%, more preferably 2.5 to 22.5 wt.-%, still more preferably 5 to 20 wt.-%, even more preferably 7.5 to 17.5 wt.-%, most preferably 10 to 15 wt.-%, and in particular 12 to 13 wt.-%, relative to the total weight of the capsule filling.

In a preferred embodiment, Tapentadol is present as the hydrochloride salt and the total content of Tapentadol hydrochloride is within the range of from 0.1 to 25 wt.-%, more preferably 2.5 to 22.5 wt.-%, still more preferably 5 to 20 wt.-%, even more preferably 7.5 to 17.5 wt.-%, most preferably 10 to 15 wt.-%, and in particular 12 to 13 wt.-%, relative to the total weight of the capsule filling.

The pharmaceutical capsule according to the invention provides immediate release of Tapentadol or a physiologically acceptable salt thereof. In this regard, immediate release is preferably understood as the opposite of prolonged release. Preferably, “immediate release” means within 30 minutes after oral administration a release of at least 80 wt.-%, more preferably at least 85 wt.-%, most preferably at least 90 wt.-% and in particular at least 95 wt.-% of the Tapentadol or physiologically acceptable salt thereof that was originally contained in the pharmaceutical capsule. The release profile may be tested under physiological conditions in simulated gastric fluid (e.g. in 900 ml 0.1 N HCl, at 75 rpm).

Preferably, the capsule filling comprises an ion exchange resin that creates an ion exchange complex with the Tapentadol or physiologically acceptable salt thereof that dissociates within 30 minutes within the gastrointestinal tract.

It has been surprisingly found that capsules comprising capsule fillings that show acceptable solubility properties and that comprise a colloidal anhydrous silica and a gum exhibit tamper resistant properties.

The parenteral tamper resistant capsule of the invention comprises a liquid excipient blend.

The term “excipient” as used herein refers to a compound that is useful in preparing a pharmaceutical composition, generally safe, non-toxic and neither biologically nor otherwise undesirable, and includes compounds that are acceptable for veterinary use as well as human pharmaceutical use.

The phrase “liquid excipient blend” means the capsule filling of the capsule except for Tapentadol or physiologically acceptable salt thereof. The liquid excipient blend comprises selected physiologically acceptable components such as a solvent, a surfactant, and a viscosity enhancer.

The liquid excipient blend may also comprise another active pharmaceutical ingredient that is not Tapentadol or physiologically acceptable salt thereof

The liquid excipient blend comprises any physiologically acceptable components so as to solubilize or miscibilize the Tapentadol or physiologically acceptable salt thereof. The liquid excipient blend of the invention solubilizes or suspends the Tapentadol or physiologically acceptable salt thereof. The solubility of the Tapentadol or physiologically acceptable salt thereof must be sufficient to solubilize a therapeutically effective amount of the Tapentadol or physiologically acceptable salt thereof. Alternatively, the Tapentadol or physiologically acceptable salt thereof may form a stable suspension. The solubility of the Tapentadol or physiologically acceptable salt thereof may be determined by mixing equivalent of 25% of the therapeutically effective amount of Tapentadol or physiologically acceptable salt thereof in the liquid excipient blend. After stirring for 18 hours at 20 to 25° C., additional 25% of the Tapentadol or physiologically acceptable salt thereof is added. This last step is repeated until the saturation solubility is reached.

The liquid excipient blend of the invention balances at least three different properties: (1) solubilization; (2) tamper resistance; and (3) immediate release. Other additional considerations include long term stability, and ease of processing.

One of the components of the liquid excipient blend is a solvent or a carrier. The capsule filling may comprise more than one solvent. The solvent is any physiologically acceptable solvent that solubilizes the Tapentadol or physiologically acceptable salt thereof and the excipients.

The solvent is generally hydrophilic or amphiphilic. Exemplary solvents include water, polyethylene glycol, propylene glycol, medium chain triglycerides, corn oil mono- and diglycerides, refined soybean oil, refined sesame oil, ethanol, phospholipid concentrates, poloxamers and medium chain partial glycerides.

The combination of water and polyethylene glycol is particularly preferred, wherein the relative weight ratio of water to polyethylene glycol is preferably within the range of from 1:100 to 1:10, more preferably 1:60 to 1:30.

Preferably, the total content of solvent is within the range of from 10 to 90 wt.-%, more preferably 20 to 85 wt.-%, still more preferably 30 to 80 wt.-%, yet more preferably 35 to 75 wt.-%, even more preferably 40 to 70 wt.-%, most preferably 45 to 65 wt.-% and in particular 50 to 60 wt.-%, relative to the total weight of the capsule filling.

When the solvent comprises water, the water content is preferably within the range of from 0.1 to 20 wt.-%, more preferably 0.3 to 15 wt.-%, still more preferably 0.5 to 10 wt.-%, yet more preferably 0.7 to 7.5 wt.-%, even more preferably 0.8 to 5.0 wt.-%, most preferably 0.9 to 2.5 wt.-% and in particular 1.0 to 1.5 wt.-%, relative to the total weight of the capsule filling.

Another component of the liquid excipient blend of the invention is a surfactant. The liquid excipient blend may comprise more than one surfactant. The surfactant is selected from any physiologically acceptable surfactants.

Preferably, the surfactant has a HLB value within the range of from 14±7, more preferably 14±5, most preferably 14±3, and in particular 14±1.

Preferably, the surfactant is nonionic.

In a preferred embodiment, the surfactant is a nonionic surfactant selected from the group consisting of glycerol monoesters with C₆₋₁₈-fatty acids, glycerol diesters with identical or different C₆₋₁₈-fatty acids, glycerol triesters with identical or different C₆₋₁₈-fatty acids, polyethylene glycol monoesters with C₆₋₁₈-fatty acids, polyethylene glycol diesters with identical or different C₆₋₁₈-fatty acids, and mixtures of any of the foregoing.

In another preferred embodiment, the surfactant is selected from the group consisting of polyoxyethylene (20) sorbitanmonolaurate, polyoxyethylene (20) sorbitanmonopalmitate, polyoxyethylene (20) sorbitanmonostearate, and polyoxyethylene (20) sorbitanmonooleate.

Exemplary surfactants include but are not limited to Polysorbate 20, Polysorbate 80, Tween 20, Tween 80, Macrogolglycerolhydroxystearate, Cremophor RH 40®, Macrogolglycerolricinoleate, Cremophor EL®, glycerolmonooleate 40, Peceolo, Macrogolglyceryl, Labrafil M 2125 CS, propyleneglycolmonolaurate FCC, Lauroglycol FCC®, Polyglycerol-b-Dioleate, propylenglycolmonocaprylate, Capryol 900, sorbitanmonolaurate, Span 200, sorbitanmonooleate, Span 800, Vitamin E-polyethylenglycolsuccinate, caprylocaproyl macrogol-8-glycerides, Labrasol®, macrogol-32-glycerol-laurate, Gelucire 44/14, glycerylmonocaprate, glycerylcaprylate, and Capmul MCM.

Preferably, the total content of surfactant is within the range of from 0.1 to 35 wt.-%, more preferably 1.0 to 32.5 wt.-%, still more preferably 5.0 to 30 wt.-%, yet more preferably 7.5 to 27.5 wt.-%, even more preferably 10 to 25 wt.-%, most preferably 12.5 to 22.5 wt.-%, and in particular 15 to 20 wt.-%, relative to the total weight of the capsule filling.

Another component of the liquid excipient blend of the invention is a viscosity enhancer, or a gelling agent. Exemplary viscosity enhancers include but are not limited to colloidal anhydrous silica, gum, and hard fat. Preferably, the viscosity enhancer comprises colloidal anhydrous silica and/or a gum.

Examples of gum include but are not limited to acacia, agar, tragacanth, guar gum, xanthan gum, locust bean gum, tara gum, karaya, gellan gum, welan gum, and rhamsan gum.

In a preferred embodiment, the liquid excipient blend comprises a combination of two viscosity enhancers, more preferably colloidal anhydrous silica in combination with a gum, more preferably colloidal anhydrous silica in combination with a gum selected from the group consisting of acacia, agar, tragacanth, guar gum, xanthan gum, locust bean gum, tara gum, karaya, gellan gum, welan gum, and rhamsan gum, and in particular colloidal anhydrous silica in combination with xanthan gum.

When the liquid excipient blend comprises a combination of colloidal anhydrous silica with a gum such as xanthan gum, the relative weight ratio of silica to gum is preferably within the range of from 1:1 to 20:1, more preferably 5:1 to 10:1.

Preferably, the total content of viscosity enhancer is within the range of from 0.1 to 10 wt.-%, more preferably, still more preferably relative to the total weight of the capsule filling.

In a preferred embodiment, the liquid excipient blend comprises an ion exchange resin. Preferably, the ion exchange resin is anionic, i.e. bears anionic functional groups that are linked, preferably covalently to a resin. Suitable anionic functional groups include but are not limited to carboxylic acid groups and sulfonic acid groups.

Preferably, the total content of ion exchange resin is within the range of from 0.1 to 25 wt.-%, more preferably 1.0 to 20 wt.-%, still more preferably 2.5 to 15 wt.-%, yet more preferably 5.0 to 12.5 wt.-%, even more preferably 6.0 to 11 wt.-%, most preferably 7.0 to 10 wt.-% and in particular 8.0 to 9.0 wt.-%, relative to the total weight of the capsule filling.

In a preferred embodiment, the liquid excipient blend comprises a plasticizer.

Examples of plasticizers include propylene glycol, glycerol, glycerin, sorbitol, and Anidrisorb. Glycerin is particularly preferred.

Preferably, the total content of plasticizer is within the range of from 0.1 to 25 wt.-%, more preferably 0.2 to 20 wt.-%, still more preferably 0.5 to 17.5 wt.-%, yet more preferably 1.0 to 15 wt.-%, even more preferably 2.0 to 12.5 wt.-%, most preferably 3.0 to 10 wt.-% and in particular 4.0 to 6.0 wt.-%, relative to the total weight of the capsule filling.

It is surprising that parenteral tamper resistant capsule fillings that show acceptable solubility properties and that comprise a colloidal anhydrous silica and a gum exhibit tamper resistant properties.

Such formulations include solvents such as medium chain triglycerides. Formulations that comprise medium chain triglycerides, colloidal anhydrous silica, and xanthan, preferably also include a polysorbate surfactant.

Other solvent and surfactant combinations in the liquid excipient blend that show surprising and unexpected tamper resistant properties when colloidal anhydrous silica and xanthan is present, include polyethylene glycol, and a surfactant selected from the group consisting of polyoxyl 40 hydrogenated castor oil, polysorbate surfactant, caprylocaproyl macrogol-8-glyceride, and glycerol. Examples of polyethylene glycol include Macrogol 400 and Macrogol 600.

Furthermore, it was unexpected and surprising to find that the liquid excipient blend comprising a phospholipid concentrate and a polysorbate surfactant also exhibit acceptable solubility and tamper resistance. The polysorbate surfactant in the formulation that exhibit the tamper resistant properties include polyoxyethylene (20) sorbitanmonolaurate, polyoxyethylene (20) sorbitanmonopalmitate, polyoxyethylene (20) sorbitanmonostearate, and polyoxyethylene(20) sorbitanmonooleate. Examples of phospholipid concentrates include Phosal 50 PG, and Lipoid PPL 600. For selected formulations, the use of a viscosity enhancer (colloidal anhydrous silica 0.5 to 1.5 wt %) was found to be helpful in order to achieve tamper resistance.

Yet another unexpected and surprising combination of liquid excipient blend components that exhibit solubility and abuse resistance is liquid excipient blend comprising polyethylene glycol, caprylocaproyl macrogol-8-glycerides, glycerol, and a viscosity enhancer. The viscosity enhancer may be a mixture of colloidal anhydrous silica and a gum.

Two examples of formulations that exhibit the desired properties are particularly preferred. One of the formulations comprises xanthan, the other pharmaceutical grade ion exchange resin such as Amberlite IR.P 64. The immediate release dissolution (in 0.1 N HCl, at 75 rpm) showed that more than 80% of Tapentadol from either of the formulations was dissolved after 30 minutes. Both formulations showed that not more than 33% of Tapentadol was detectable in syringe after boiling of the capsule filling with 5 ml water.

The formulations of Inventive Examples 16 and 18 comprise Medium Chain Triglycerides (27.3% and 28.2%, respectively), Polysorbate 80 (50.9%, 52.7%), Span 20 (12.7%, 13.2%), Colloidal anhydrous silica (4.5%, 3.5%), and xanthan gum (4.5%, 2.7%). These compositions are yellowish, homogeneous, liquid suspensions, which formed a gel and non-stable bubbles at boiling with water. 250 and 1000 g of the capsule filling could hardly be drawn up in the syringe and formed of a milky foam. Both formulations showed good dispersibility after disintegration of capsules (4.5 minutes). Approximately 80% of the Tapentadol was dissolved after 20 to 25 minutes and 100% after approx. 30 minutes.

Other solvent and surfactant combinations in the liquid excipient blend that show surprising and unexpected tamper resistant properties when colloidal anhydrous silica and xanthan is present, include polyethylene glycol, and a surfactant selected from the group consisting of polyoxyl 40 hydrogenated castor oil, polysorbate surfactant, caprylocaproyl macrogol-8-glyceride, and glycerol. Examples of polyethylene glycol include Macrogol 400 and Macrogol 600.

The 3:1 mixtures of Macrogol 400 with the surfactants Cremophor RH 40, Polysorbat 80 and Labrasol in Inventive Examples Nos. 30, 31, and 32 and Colloidal anhydrous Silica/Xanthan as gelling agents gave yellowish homogeneous suspensions, which formed a gel and a partially persisting foam at boiling in the water. The solution was not syringable but the dispersibility of the gel was poor due to formation of a compact mass after 6 minutes in the dispersion medium.

Tamper resistant properties were also observed with the use of replacing Macrogol 400 (see Comparative Example 35) by Macrogol 600 and xanthan. An intensive frothing milky emulsion resulted after boiling with water, which was not syringable. Both selected formulations of Examples 35 and 36 were easily dispersible in 0.1 N HCl at 100 rpm 80% of the capsule filling were dissolved after 20 minutes and 100% after 30 minutes.

Two examples of formulations according to the invention that exhibit the desired properties and that include Tapentadol or a physiologically acceptable salt thereof are particularly preferred. One of the formulations comprises xanthan (Formulation B), the other pharmaceutical grade ion exchange resin

Amberlite IRP 64 (Formulation A). Preferred formulations comprise about 50% to 60% polyethylene glycol, 15% to 20% Caprylocaproyl Macrogol-8-glycerides, 3 to 6% colloidal anhydrous silica, 3 to 6% glycerol, 1% to 2% water. Formulation A comprises Macrogol 600 Ph. Eur. (479.02 mg/capsule, 51.0% of fill), Caprylocaproyl Macrogol-8-glycerides Ph.Eur. (160.00 mg, 17.0%), Colloidal anhydrous Silica Ph.Eur. (45.00 mg, 4.8%), Glycerol, anhydrous Ph. Eur. (47.00 mg, 5.0%), Water, purified; Ph.Eur. (12.50 mg, 1.3%), and Amberlite IRP 64 (80.00 mg, 8.5%). Formulation B comprises Macrogol 600 Ph. Eur. (554.2 mg/capsule, 58.3% of fill), Caprylocaproyl Macrogol-8-glycerides Ph.Eur. (175.00 mg, 18.4%), Colloidal anhydrous Silica Ph.Eur. (40.00 mg, 4.2%), Glycerol, anhydrous Ph. Eur. (47.00 mg, 4.9%), Water, purified, Ph.Eur. (12.50 mg, 1.3%), and xanthan (5.00 mg, 0.5%). The capsule shell comprises Glycerol 85% Ph.Eur.: 106.43 mg (97.92-114.94 mg), Dry substance of Anidrisorb 85/70: 30.87 mg (28.40-33.34 mg); Gelatin 160 bloom. Ph.Eur. NF (bovine, kosher, Halal) 244.17 mg (224.64-263.70 mg).

It is hypothesized that in the above formulations each of the components has a specific function. Macrogol 600 is hydrophilic solvent agent for the water soluble drugs. Caprylocaproylmacrogol 8 glycerides are a hydrophilic surfactant (HLB 14) and solvent that improves dissolution and bioavailability, and causes bubbling at boiling of the capsule capsule filling with water. Colloidal anhydrous silica is a viscosity enhancer in order to stabilize the hydrophilic fall suspension. Glycerol is a plasticizer in the capsule filling to reduce migration effects from shell to the capsule filling.

Water increases drug solubility, reduces gelling agent concentration with positive effect on immediate release dissolution properties.

With respect to xanthan in formulation B, it is hypothesized that this hydrogelling agent is suspended in the capsule fill, but at boiling of the capsule capsule filling with hot water, it forms highly viscous gels as physical barrier. This reduces syringability and injectability.

With respect to Amberlite IRP 64 in formulation A, it is hypothesized that the HCl salt of the quarternary ammonium ion of the active substance forms a drug ion exchange complex with a weak acidic cationic resin (—COOH group) in Amberlite IRP 64. This ion pair complex is stable in the formulation, but is immediately released in the stomach environment, as the —COOH group of the resin has a high affinity to the H⁺ Ions present in the stomach, Additionally to this fast release of the Tapentadol or physiologically acceptable salt thereof in 0.1 N HCl, an increase of the viscosity at boiling of the formulations containing the Polyacrilex resin was achieved. Amberlite IRP64 is inducted in the FDA inactive ingredients list under Polacrilin and already used in human drugs.

The following results of the relevant parameters in vitro dissolution and abuse resistance test (syringability) have been obtained. The immediate release dissolution (in 0.1 N HCl, at 75 rpm) showed that more than 80% of either of the formulations was dissolved after 30 minutes.

Another aspect of the invention relates to the capsule according to the invention as described above for use in the treatment of pain, preferably acute pain, preferably by oral administration.

Another aspect of the invention relates to a method of treating pain, preferably acute pain, comprising the preferably oral administration to a capsule according to the invention as described above to a subject in need thereof.

Another aspect of the invention relates to the use of the capsule according to the invention for preventing parenteral abuse of Tapentadol or a physiologically acceptable salt thereof.

EXAMPLES

The following examples further illustrate the invention but are not to be construed as limiting its scope.

Part a) Capsule Fillings—Liquid Excipient Blends Comparative Example 1

15.8 g of medium chain triglycerides, 2.5 g of hydrogenated soya bean oil, 41.7 g of hard fat, 3.3 g of Povidone K 30, and 3.3 g of polyoxyl 40 hydrogenated castor oil were mixed to obtain a homogenous mixture. The mixture was firm at room temperature, and flowable and pourable at 30° C. When the mixture is boiled with water (ca. 250 mg of the mixture in 5 mL of water), hard fat separates on cooling down. No air bubbles were formed at boiling. The aqueous phase was syringable with a 20 gauge needle, whereas small particles of hard fat were also observed in the syringe. After disintegration of the shell of lab filled capsules at about 25 minutes, the fall was dispersed with remaining fat particles in the dissolution medium and oil film on the surface.

Comparative Example 2

15.8 g of medium chain triglycerides, 2.5 g of hydrogenated soya bean oil, 41.7 g of hard fat, 3.3 g of Povidone K 30, and 3.3 g of polysorbate 80 h were mixed to obtain a homogenous mixture. 30 The mixture was firm at room temperature, and flowable and pourable at 30° C. When the mixture is boiled with water, hard fat separates on cooling down. No air bubbles were formed at boiling and the aqueous phase was syringable, whereas small particles of hard fat were also observed in the syringe. After disintegration of the shell at about 25 minutes, the capsule filling was dispersed with remaining fat particles in the dissolution medium and oil film on the surface.

Comparative Example 3

15.8 g of medium chain triglycerides, 2.5 g of hydrogenated soya bean oil, 41.7 g of hard fat, 3.3 g of Povidone K 30, and 3.3 g of polyoxyl 35 castor oil were mixed to obtain a homogenous mixture. The mixture was firm at room temperature, and flowable and pourable at 30° C. When the mixture is boiled with water, hard fat separates on cooling down. No air bubbles were formed at boiling and the aqueous phase was syringable, whereas small particles of hard fat were also observed in the syringe. After disintegration of the shell at about 25 minutes, the capsule filling was dispersed with remaining fat particles in the dissolution medium and oil film on the surface.

Comparative Example 4

45.0 g of medium chain triglycerides, 10.0 g of hydrogenated soya bean oil, and 10.4 g of polyoxyl 40 hydrogenated castor oil were mixed to obtain a homogenous mixture. The mixture was soft, flowable and pourable at room temperature. The sample exhibits a sheen of oil and sedimentation.

Comparative Example 5

45.0 g of medium chain triglycerides, 10.0 g of hydrogenated soya bean oil, and 10.0 g of polysorbate 80 were mixed to obtain a homogenous mixture. The mixture was soft, flowable and pourable at room temperature. The sample exhibits a sheen of oil and sedimentation.

Comparative Example 6

45.0 g of medium chain triglycerides, 10.0 g of hydrogenated soya bean oil, and 10.0 g of polyoxyl 35 castor oil were mixed to obtain a homogenous mixture. The mixture was soft, flowable and pourable at room temperature. The sample exhibits a sheen of oil and sedimentation.

Comparative Example 7

10.0 g of medium chain triglycerides and 40.0 g of polysorbate 80 were mixed to obtain a homogenous mixture. The mixture was a clear yellowish solution. When the solution is boiled with water, no frothing is observed.

Comparative Example 8

41.0 g of caprylocaproyl macrogol-8-glyceride, 6.5 g of medium chain triglycerides, and 2.5 g of polyglycerol-6-dioleate were mixed to obtain a clear yellowish solution. Upon addition of water, a white emulsion is obtained. No frothing is observed upon boiling with water.

Comparative Example 9

8.0 g of medium chain triglycerides, 25.6 g of polysorbate 80, and 6.4 g of sorbitanmonolaurate were mixed to obtain a homogenous mixture. The mixture was a clear yellowish solution. Upon addition of water, a turbid solution is obtained. Little frothing is observed upon boiling with water. The turbid solution can be drawn up into the syringe with little frothing.

Comparative Example 10

12.0 g of medium chain triglycerides, 22.4 g of polysorbate 80, and 5.6 g of sorbitanmonolaurate were mixed to obtain a homogenous mixture. The mixture was a clear yellowish solution. Upon addition of water, an almost clear solution is obtained. Little frothing is observed upon boiling with water. The solution can be drawn up into the syringe with little frothing.

Comparative Example 11

16.0 g of medium chain triglycerides, 19.2 g of polysorbate 80, and 4.8 g of sorbitanmonolaurate were mixed to obtain a homogenous mixture. The mixture was a clear yellowish solution. Upon addition of water, a turbid solution is obtained. Little frothing is observed upon boiling with water. The milky solution can be drawn up into the syringe with little frothing.

Comparative Example 12

20.0 g of medium chain triglycerides, 16.0 g of polysorbate 80, and 4.0 g of sorbitanmonolaurate were mixed to obtain a homogenous mixture. The mixture was a clear yellowish solution. Upon addition of water, a white emulsion is obtained. Little frothing is observed upon boiling with water. The milky emulsion can be drawn up into the syringe with little frothing.

Comparative Example 13

24.0 g of medium chain triglycerides, 12.8 g of polysorbate 80, and 3.2 g of sorbitanmonolaurate were mixed to obtain a homogenous mixture. The mixture was a clear yellowish solution. Upon addition of water, a white emulsion is obtained. Little frothing is observed upon boiling with water. The milky emulsion can be drawn up into the syringe with little frothing.

Inventive Example 14

12.0 g of medium chain triglycerides, 22.4 g of polysorbate 80, 5.6 g of sorbitanmonolaurate, 1.5 g of colloidal anhydrous silica, and 4.0 g of xanthan were mixed to obtain a homogenous yellowish suspension that is a pourable liquid. Upon addition of water, the suspension forms a gel. Upon boiling with water, frothing is observed, but the foam does not persist. The solution cannot be drawn up into the syringe. The yellowish suspension was used to fill a tube-shaped capsule. The capsule was then tested for dispersibility in 0.1 N HCl with the Paddle dissolution apparatus at 100 rpm, after about 20 minutes, about 40% if the capsule filling dispersed.

Comparative Example 15

12.0 g of medium chain triglycerides, 22.4 g of polysorbate 80, 5.6 g of sorbitanmonolaurate, and 2.0 g of colloidal anhydrous silica were mixed to obtain a yellowish gel that is almost clean. Upon addition of water, a white emulsion forms. Upon boiling with water, little frothing is observed. The milky solution can be drawn up into the syringe.

Inventive Example 16

12.0 g of medium chain triglycerides, 22.4 g of polysorbate 80, 5.6 g of sorbitanmonolaurate, 2.0 g of colloidal anhydrous silica, and 2.0 g of xanthan were mixed to obtain a homogenous yellowish suspension that is pourable. Upon addition of water, a gel forms. Upon boiling with water, frothing is observed and the foam does not persist. The milky solution can hardly be drawn up into the syringe. At higher concentration of the suspension (1 g in 5 mL of water), the resulting mixture exhibits very strong frothing, and the mixture cannot be drawn into the syringe. The yellowish suspension was tested for dispersibility. After about 4.5 minutes the capsule opened; after about 20 to 25 minutes about 80% of the capsule filling dissolved. After about 30 to 35 minutes 100% of the capsule filling was dissolved.

Inventive Example 17

12.0 g of medium chain triglycerides, 22.4 g of polysorbate 80, 5.6 g of sorbitanmonolaurate, 1.5 g of colloidal anhydrous silica, and 1.5 g of xanthan were mixed to obtain a homogenous yellowish suspension that is pourable. Upon addition of water, a gel forms. Upon boiling with water, frothing is observed and the foam does not persist. The milky solution can hardly be drawn up into the syringe. At higher concentration of the suspension, the resulting mixture exhibits very strong frothing, and the mixture can hardly be drawn into the syringe. The foam can be pressed out.

Inventive Example 18

12.0 g of medium chain triglycerides, 22.4 g of polysorbate 80, 5.6 g of sorbitanmonolaurate, 1.5 g of colloidal anhydrous silica, and 1.0 g of xanthan were mixed to obtain a homogenous yellowish suspension that is pourable. Upon addition of water, a gel forms. Upon boiling with water, frothing is observed and the foam does not persist. The milky solution can hardly be drawn up into die syringe. At higher concentration of the suspension, the resulting mixture exhibits very strong frothing, and the mixture can hardly be drawn into the syringe. The foam can be pressed out. The yellowish suspension was tested for dispersibility. After about 4.5 minutes the capsule opened; after about 20 to 25 minutes about 80% of the capsule filling dissolved. After about 30 to 35 minutes 100% of the fit was dissolved.

Comparative Example 19

42.5 g of macrogol 400, 6.3 g of medium chain triglycerides, 6.3 g of polysorbate 80, and 1.3 g of colloidal anhydrous silica were mixed to obtain an opalescent, yellowish solution. Upon addition of water, a white emulsion is obtained. Upon boiling with water, no frothing is observed.

Comparative Example 20

42.5 g of macrogol 400, 6.3 g of medium chain triglycerides, 6.3 g of polyoxyl 40 hydrogenated castor oil, and 1.3 g of colloidal anhydrous silica were mixed to obtain an opalescent, yellowish solution. Upon addition of water, a white emulsion is obtained. Upon boiling with water, no frothing is observed.

Comparative Example 21

42.5 g of macrogol 400, 6.3 g of medium chain triglycerides, 6.3 g of polyoxyl 35 castor oil, and 1.3 g of colloidal anhydrous silica were mixed to obtain an opalescent, yellowish solution. Upon addition of water, a white emulsion is obtained. Upon boiling with water, no frothing is observed.

Comparative Example 22

38.8 g of macrogol 400, 6.3 g of propylene glycol, 2.5 g of water, 6.3 g of polysorbate 80, and 2.5 g of Povidone K 30 were mixed to obtain a pale yellow, turbid solution that separated.

Comparative Example 23

38.8 g of macrogol 400, 6.3 g of propylene glycol, 2.5 g of water, 6.3 g of polysorbate 20, and 2.5 g of Povidone K 30 were mixed to obtain a homogenous pale yellow, turbid solution. Upon addition of water, a clean solution is obtained. Upon boiling with water, no frothing is observed.

Comparative Example 24

38.8 g of macrogol 400, 6.3 g of propylene glycol, 2.5 g of water, 6.3 g of polyoxyl 40 hydrogenated castor oil, and 2.5 g of Povidone K 30 were mixed to obtain a homogenous pale yellow, almost clear solution. Upon addition of water, a clear solution is obtained. Upon boiling with water, no frothing is observed.

Comparative Example 25

38.8 g of macrogol 600, 6.3 g of propylene glycol, 2.5 g of water, 6.3 g of polysorbate 80, and 2.5 g of Povidone K 30 were mixed to obtain a pale yellow, turbid solution that separated.

Comparative Example 26

38.8 g of macrogol 600, 6.3 g of propylene glycol, 2.5 g of water, 6.3 g of polysorbate 80, and 2.5 g of Povidone K 30 were mixed to obtain a pale yellow, turbid solution that separated.

Comparative Example 27

35.0 g of macrogol 600, 6.3 g of propylene glycol, 2.5 g of water, 6.3 g of polyoxyl 35 castor oil, and 6.3 g of xanthan gum were mixed to a mixture that separated and sedimented.

Comparative Example 28

35.0 g of macrogol 600, 6.3 g of propylene glycol, 2.5 g of water, 6.3 g of polysorbate 20, and 6.3 g of xanthan gum were mixed to a mixture that separated and sedimented.

Comparative Example 29

35.0 g of macrogol 600, 6.3 g of propylene glycol, 2.5 g of water, 6.3 g of polyoxyl 40 hydrogenated castor oil, and 6.3 g of xanthan gum were mixed to a mixture that separated and sedimented.

Inventive Example 30

30.0 g of macrogol 400, 10.0 g of polyoxyl 40 hydrogenated castor oil, 5.0 g of xanthan gum, and 1.0 g of colloidal anhydrous silica were mixed to obtain a homogeneous yellowish suspension that is pourable. The suspension forms a gel when mixed with water. Upon boiling, the gel froths, wherein the foam partially persists. The resulting solution cannot be drawn up in a syringe. The yellowish suspension was tested for dispersibility. After about 60 minutes the capsule filling is a compact mass, with less than 50% of the capsule filling dissolved.

Inventive Example 31

30.0 g of macrogol 400, 10.0 g of polysorbate 80, 5.0 g of xanthan gum, and 1.0 g of colloidal anhydrous silica were mixed to obtain a homogeneous yellowish suspension that is pourable. The suspension forms a gel when mixed with water. Upon boiling, the gel froths, wherein the foam does not persist. The resulting solution cannot be drawn up in a syringe. The yellowish suspension was tested for dispersibility as above. After about 60 minutes the capsule filling 25 is a compact mass, with less than 50% of the capsule filling dissolved.

Inventive Example 32

30.0 g of macrogol 400, 10.0 g of caprylocaproyl macrogol-8-glyceride, 5.0 g of xanthan gum, and 1.0 g of colloidal anhydrous silica were mixed to obtain a homogeneous yellowish suspension that is pourable. The suspension forms a gel when mixed with water. Upon boiling, the gel froths, wherein the foam partially persists. The resulting solution cannot be drawn up in a syringe. The yellowish suspension was tested for dispersibility as above. After about 60 minutes the capsule filling is a compact mass, with less than 50% of the capsule filling dissolved.

Comparative Example 33

30.0 g of macrogol 400, 10.0 g of polyxyl 40 hydrogenated castor oil, and 2.0 g of colloidal anhydrous silica were mixed to obtain a colorless gel that is pourable. The gel forms a white emulsion when mixed with water. Upon boiling, no frothing is observed. The resulting solution cannot be drawn up in a syringe. The formulation was tested for dispersibility as above. After about 20 minutes, about 90% of the capsule filling dispersed.

Comparative Example 34

30.0 g of macrogol 400, 10.0 g of polysorbate 80, and 2.0 g of colloidal anhydrous silica were mixed to obtain a turbid yellowish gel that is barely pourable. The gel forms a white emulsion when mixed with water. Upon boiling, no frothing is observed. The resulting solution can be drawn up in a syringe. The formulation was tested for dispersibility as above. After about 20 minutes, about 80% of the capsule filling dispersed.

Comparative Example 35

30.0 g of macrogol 400, 10.0 g of caprylocaproyl macrogol-8-glyceride, and 2.0 g of colloidal anhydrous silica were mixed to obtain a clear yellowish gel that is pourable. The gel forms a white emulsion when mixed with water. Upon boiling, strong frothing is observed. The resulting solution can be drawn up in a syringe. For the higher concentration of the formulation in water, the resulting milky emulsion exhibits strong frothing and can be drawn up into the syringe. The dispersibility test showed that after about 20 minutes 80% of the capsule filling was dissolved, and after 30 minutes, all of the capsule filling was dissolved.

Inventive Example 36

30.0 g of macrogol 400, 10.0 g of caprylocaproyl macrogol-8-glyceride, 2.0 g of colloidal anhydrous silica, and 0.8 g of xanthan were mixed to obtain a turbid yellowish gel that is barely pourable. The mixture forms a gel when mixed with water. Upon boiling, little frothing is observed. The resulting mixture can be drawn up in a syringe. For the higher concentration of the formulation in water, the resulting mixture cannot be drawn up into the syringe, with strong frothing.

Inventive Example 37

30.0 g of macrogol 400, 10.0 g of caprylocaproyl macrogol-8-glyceride, 2.0 g of colloidal anhydrous silica, and 2.0 g of xanthan were mixed to obtain a turbid yellowish gel that is barely pourable. The mixture forms a gel when mixed with water. Upon boiling, little frothing is observed. The resulting mixture can be drawn up in a syringe. For the higher concentration of the formulation in water, the resulting mixture cannot be drawn up into the syringe, with strong frothing. The dispersibility test showed that after about 20 minutes 80% of the fall was dissolved, and after 30 minutes, all of the capsule filling was dissolved.

Comparative Example 38

33.8 g of medium chain partial glycerides, 6.3 g of polysorbate 80, and 3.8 g of Povidone K 30 were mixed to obtain a clear pale yellow solution. The mixture forms a grey emulsion when mixed with water. Upon boiling, no frothing is observed.

Comparative Example 39

33.8 g of medium chain partial glycerides, 6.3 g of polysorbate 20, and 3.8 g of Povidone K 30 were mixed to obtain a clear pale yellow solution. The mixture forms a grey translucent emulsion when mixed with water. Upon boiling, no frothing is observed.

Comparative Example 40

33.8 g of medium chain partial glycerides, 6.3 g of polyoxyl 40 hydrogenated Castor oil, and 3.8 g of Povidone K 30 were mixed to obtain a clear pale yellow solution. The mixture forms a white emulsion when mixed with water. Upon boiling, no frothing is observed.

Comparative Example 41

25.0 g of medium chain partial glycerides, 18.0 g of polysorbate 80, and 18.0 g of propylene glycol were mixed to obtain a clear pale yellow solution. The mixture forms a white emulsion when mixed with water. Upon boiling, no frothing is observed. The milky emulsion can be drawn up into the syringe.

Comparative Example 42

25.0 g of medium chain partial glycerides, 18.0 g of polysorbate 20, and 18.0 g of propylene glycol were mixed to obtain a clear pale yellow solution. The mixture forms a white emulsion when mixed with water. Upon boiling, no frothing is observed.

Comparative Example 43

25.0 g of medium chain partial glycerides, 6.3 g of polysorbate 20, and 3.8 g of Povidone K 30 were mixed to obtain a clear pale yellow solution. The mixture forms a grey translucent emulsion when mixed with water. Upon boiling no frothing is observed.

Comparative Example 44

35.0 g of medium chain partial glycerides and 15.0 g of lipoid PPL-600 were mixed to obtain a clear reddish brown solution. When mixed with water, the mixture spreads, but does not form an emulsion. Upon boiling, frothing is observed, but it does not persist. The milky emulsion can be drawn up into the syringe.

Comparative Example 45

25.0 g of medium chain partial glycerides, 15.0 g of lipoid PPL-600, and 10.0 g of propylene glycol were mixed to obtain a clean reddish brown solution. When mixed with water, the mixture spreads, but does not form an emulsion. Upon boiling, frothing is observed, but it does not persist. The milky emulsion can be drawn up into the syringe.

Comparative Example 46

20.0 g of medium chain partial glycerides, 10.0 g of lipoid PPL-600, and 20.0 g of propylene glycol were mixed to obtain a clear reddish brown solution. When mixed with water, the mixture spreads, but does not form an emulsion. Upon boiling, frothing is observed, but it does not persist. The milky emulsion can be drawn up into the syringe.

Comparative Example 47

25.0 g of lipoid PPL-600, and 25.0 g of macrogol 600 were mixed to obtain a mixture that separates and solids appear within one day of storage.

Comparative Example 48

25.0 g of lipoid PPL-600, and 25.0 g of macrogol 400 were mixed to obtain a mixture that separates alter one day of storage.

Comparative Example 49

25.0 g of lipoid PPL-600, and 25.0 g of propylene glycol were mixed to obtain a mixture that separates and solids appear within one day of storage.

Comparative Example 50

10.0 g of lipoid PPL-600, 10.0 g of macrogol 600, and 5.0 g of medium chain partial glycerides were mixed to obtain a mixture that separates.

Comparative Example 51

10.0 g of lipoid PPL-600, 10.0 g of macrogol 400, and 5.0 g of medium chain partial glycerides were mixed to obtain a mixture that separates.

Comparative Example 52

10.0 g of lipoid PPL-600, 10.0 g of propylene glycol, and 5.0 g of medium chain partial glycerides were mixed to obtain a clear reddish brown solution. When mixed with water, a yellowish emulsion forms. Upon boiling, frothing is observed, but it does not persist. The milky emulsion can be drawn up into the syringe.

Comparative Example 53

12.5 g of lipoid PPL-600, 18.8 g of polysorbate 80, and 18.8 g of propylene glycol were mixed to obtain a clear reddish brown solution. When mixed with water the mixture turns turbid. Upon boiling, little frothing is observed. The turbid emulsion can be drawn up into the syringe.

Comparative Example 54

25.0 g of lipoid PPL-600, 12.5 g of polysorbate 80, and 12.5 g of propylene glycol were mixed to obtain a clear yellow-brown solution. When mixed with water a white emulsion forms. Upon boiling, little frothing is observed, and the foam does not persist. The milky emulsion can be drawn up into the syringe.

Inventive Example 55

37.5 g of lipoid PPL-600, 6.3 g of polysorbate 80, and 6.3 g of propylene glycol were mixed to obtain a clean reddish-brown solution. When mixed with water a white emulsion forms. Upon boiling, frothing is observed, and the foam partially persists. It is very difficult to draw up the milky emulsion into the syringe.

Inventive Example 56

20.0 g of Phosal 50 PG and 2.0 g of polysorbate 80 were mixed to obtain a clear yellow solution. A yellowish emulsion forms when mixed with water, partially forming a gel. Upon boiling, frothing is observed, and the foam partially persists. Although it is possible to draw the frothy milky emulsion obtained after boiling into the syringe, for the higher concentration, very strong frothing is observed, and the milky emulsion cannot be drawn into the syringe. The dispersibility test showed that after about 10 to 15 minutes 100% of the capsule filling was finely dispersed.

Comparative Example 57

20.0 g of Phosal 50 PG and 2.0 g of polyoxyl 40 hydrogenated castor oil were mixed to obtain a clear yellow solution. A yellowish emulsion forms when mixed with water, partially forming a gel. Upon boiling, frothing is observed, and the foam partially persists. The resulting milky emulsion can be drawn into the syringe. The dispersibility test showed that after about 15 minutes 100% of the capsule filling was dispersed.

Comparative Example 58

20.0 g of Phosal 50 PG and 2.0 g of sorbitanmonolaurate were mixed to obtain a clear yellow solution. A yellowish emulsion forms when mixed with water, partially forming a gel. Upon boiling, frothing is observed, and the foam partially persists. The resulting milky emulsion can be drawn into the syringe. The dispersibility test showed that after about 15 minutes 100% of the capsule filling was dispersed.

Inventive Example 59

20.0 g of Phosal 50 PG, 2.0 g of polysorbate 80, and 1.5 g of colloidal anhydrous silica were mixed to obtain a clear yellow solution. A yellowish emulsion forms when mixed with water, partially forming a gel. Upon boiling, frothing is observed, and the foam partially persists. It is difficult to draw the milky emulsion into the syringe.

Inventive Example 60

20.0 g of Phosal 50 PG, 2.0 g of polysorbate 80, 1.5 g of colloidal anhydrous silica, and 1.5 g of xanthan were mixed to obtain a yellow suspension. A yellowish emulsion forms when mixed with water, partially forming a gel. Upon boiling, frothing is observed, and the foam partially persists. It is difficult to draw the milky emulsion into the syringe. At the higher concentrations, the formulation separates, and the aqueous phase can be drawn into the syringe.

Inventive Example 61

9.0 g of Phosal 50 PG, 1.0 g of polysorbate 80, and 1.0 g of water were mixed to obtain a turbid yellow suspension. A yellowish emulsion forms when mixed with water, partially forming a gel. Upon boiling, frothing is observed, and the foam partially persists. Although it is possible to draw the frothy milky emulsion obtained after boiling into the syringe, for the higher concentration, very strong frothing is observed, and the milky emulsion cannot be drawn into the syringe. The dispersibility test showed that after about 20 minutes 100% of the capsule filling was finely dispersed.

Comparative Example 62

9.0 g of Phosal 50 PG, 1.0 g of polysorbate 80, 0.75 g of water, and 0.25 g of ethanol were mixed to obtain an almost clear yellow solution. A yellowish emulsion forms when mixed with water, partially forming a gel. Upon boiling, frothing is observed, and the foam partially persists. The milky emulsion can be drawn into the syringe.

Inventive Example 63

9.0 g of Phosal 50 PG, 1.0 g of polysorbate 80, 0.5 g of water, and 0.5 g of ethanol were mixed to obtain a clear yellow suspension. A yellowish emulsion forms when mixed with water, partially forming a gel. Upon boiling, frothing is observed, and the foam partially persists. Although it is possible to draw the frothy milky emulsion obtained after boiling into the syringe, for die higher concentration, very strong frothing is observed, and the milky emulsion cannot be drawn into the syringe. The dispersibility test showed that after about 10 minutes 100% of the capsule filling was finely dispersed.

Comparative Example 64

20.0 g of Phosal 50 PG, 2.0 g of sorbitanmonoloaurate, and 1.5 g of colloidal anhydrous silica were mixed to obtain an almost clean yellow suspension. A yellowish emulsion forms when mixed with water, partially forming a gel. Upon boiling, frothing is observed, and the foam partially persists. It is very difficult to draw the frothy milky emulsion into the syringe.

Comparative Example 65

20.0 g of Phosal 50 PG, 2.0 g of sorbitanmonoloaurate, and 1.5 g of colloidal anhydrous silica and 1.5 g of xanthan were mixed to obtain a yellow suspension. A yellowish emulsion forms when mixed with water, partially forming a gel. Upon boiling, frothing is observed, and the foam partially persists. It is very difficult to draw the frothy milky emulsion into the syringe.

Comparative Example 66

10.0 g of propylene glycolmonolaurate and 5.0 g of Polyoxyl 40 hydrogenated castor oil were mixed to obtain a white, turbid mixture, which separated after approximately 2 days. A flocculent emulsion forms when mixed with water. No frothing is observed upon boiling.

Comparative Example 67

10.0 g of propylene glycolmonolaurate and 5.0 g of labrafil M 2125 CS were mixed to obtain a clear yellowish solution. The solution separates when mixed with water. No frothing is observed upon boiling.

Comparative Example 68

10.0 g of propylene glycolmonolaurate and 5.0 g of polysorbate 80 were mixed to obtain a clear yellowish solution. A white emulsion forms when the solution is mixed with water. No frothing is observed upon boiling.

Comparative Example 69

10.0 g of propylene glycolmonolaurate and 5.0 g of caprylocaproylmacrogol-8-glyceride were mixed to obtain a clear colorless solution. A white emulsion forms when the solution is mixed with water. No frothing is observed upon boiling.

Comparative Example 70

10.0 g of propylene glycolmonolaurate and 5.0 g of lipoid PPL-600 were mixed to obtain a clear yellowish solution. Upon addition of water, the solution partially formed a gel and separated. No frothing is observed upon boiling.

Comparative Example 71

10.0 g of propylene glycolmonolaurate and 5.0 g of macrogol-32-glycerollarate were mixed to obtain a white solid mass.

Comparative Example 72

2.0 g of gelucire 44114 and 8.0 g of Lipoid PPL-600 were mixed to obtain a yellow-brown solid mass.

Comparative Example 73

2.0 g of gelucire 44114 and 8.0 g of Labrafil M 2125 CS were mixed to obtain a turbid, yellowish, pasty liquid that separated. Upon addition of water, a white emulsion forms. No frothing is observed upon boiling.

Comparative Example 74

2.0 g of gelucire 44114 and 8.0 g of medium chain partial glycerides were tnixed to obtain a clear yellowish solution. Upon addition of water, a white emulsion forms. No frothing is observed upon boiling.

Comparative Example 75

2.0 g of gelucire 44/14 and 8.0 g of macrogol 600 were mixed to obtain a white solid mass.

Comparative Example 76

2.0 g of gelucire 44/14 and 8.0 g of propylene glycolmonolaurate were mixed to obtain a white, turbid solution that separated. Upon addition of water, a white emulsion forms. No frothing is observed upon boiling.

Comparative Example 77

2.0 g of gelucire 44/14 and 8.0 g of corn oil mono-1 di-1 tri-glycerides were mixed to obtain a clear yellowish solution that solidifies after 1 to 2 days. Upon addition of water, a white emulsion forms. No frothing is observed upon boiling.

Comparative Example 78

25.0 g of polysorbate 80, 12.5 g of ethanol, and 12.5 g of propylene glycol were mixed to obtain a clear yellowish solution. Upon addition of water, a clear solution forms. Frothing is observed upon boiling, but the foam does not persist.

Comparative Example 79

5.0 g of macrogol-32-glycerollaurate, 37.5 g of polyglycerol-6-diolate, and 20.0 g of propylene glycol were mixed to obtain a mixture that separates.

Comparative Example 80

10.0 g of macrogol-32-glycerollaurate, 10.0 g of polyglycerol-6-diolate, and 20.0 g of propylene glycol were mixed to obtain a mixture that separates, and partly solidifies.

Comparative Example 81

15.0 g of macrogol-32-glycerollaurate, 5.0 g of polyglycerol-6-diolate, and 20.0 g of propylene glycol were mixed to obtain a mixture that separates, and partly solidifies.

Comparative Example 82

25.0 g of polysorbate 80 and 25.0 g of glyceryl-monocapratel-caprylate were mixed to obtain a clear yellowish solution. Upon mixing with water, a white emulsion if obtained. Little frothing is observed upon boiling.

Part b) Capsule Fillings—Liquid Excipient Blends in Combination with Tapentadol Hydrochloride

Inventive Example 83

A Macrogol formulation with Amberlite IRP 64 having the following composition was prepared:

mg/capsule Macrogol 600 479.02 Caprylocaproyl Macrogol-glycerides 160.00 Colloidal Silicon Dioxide 45.00 Glycerol anhydrous 47.00 Water, purified 12.50 Amberlite IRP 64 80.00 Tapentadol HCl 116.48 Fill weight 940.00 Density: 1.173 Volume: 12.98 minims Capsule shape: 13 oblong

For the purpose of the specification, the unit “minims” is to be regarded as “imperial minims” (U.K.), 1 imperial minim corresponding to about 59.19 μl.

—Visual Homogeneity Up to 7 Days Storage:

The white homogeneous fill suspension was stable and proper flowable directly after preparation up to 7 days storage. After 2 days up to 7 day storage a slight sedimentation was observed. After homogenization the fill suspension was good flowable and homogenous. Based on these properties of the fill we decided to use the 30 l stirrable machine container as transfer vessel for manufacture of the pilot batch in order to enable continuous stirring before and during the encapsulation process.

—Flowability:

Strength 10 s to 19 s: 1.01 (Claim: 0.1-2.0). The data prove the food flowability of the fill mass.

—Viscosity at 25° C.:

The viscosity of the Amberlite formulation after 1 day (1001 mPas) and 7 days (1679 mPas) comply with the requirements (750-2000 mPas). No increase of viscosity at storage of the fill was observed. The results prove the suitability of the fill for encapsulation. Possible interactions with the shell were tested with manufacture of a placebo batch.

The properties of the capsules were further investigated:

Within manufacturing process of the capsules, the following parameters were tested.

-   -   Determination of IPC fill weight at the encapsulation step     -   Drying profile with overdrying for 7 days     -   Migration profile of Glycerol during manufacturing, drying and         overdrying

The dried capsules were tested regarding the following parameters:

-   -   Appearance     -   Seam thickness     -   Fill and shell weight     -   Mechanical stability     -   Disintegration     -   Capsule dimensions.

Results of investigation on dried capsules:

a) Appearance: The specification of a light pink 13 oblong capsule containing a white fill suspension was met. b) Viscosity of the fill: The viscosity of the fill mass after preparation of the fill mass was 705 mPas. It is slightly lower than the data of the fill lab sample (840 mPas). Nevertheless the data comply with the specification (500-2000 mPas) and prove the suitability for encapsulation. c) Seam thickness: Average seam thickness of the lower and upper seams (12/1000 inch upper seam, 14/1000 inch lower seam) are above the specified limits (min. 4/1000 inch). d) Fill and shell weight: Total fill and shell weight of 20 dried capsules was determined. The standard deviation for the fill is 3.8% for the shell 5.7%. Due to migration of water and Glycerol from fill to shell, the average capsule fill weight 1033.7 mg is about 8.8% (corresponding to 83.7 mg) above the nominal fill weigh 950 mg. The shell weight is within the specified limits documented in the Formula Certificate (average 405.6 mg/363.9-427.2 mg). This phenomenon is typical for Macrogol formulations. e) Disintegration and dispersibility

Disintegration in water at 37° C.: After 3 minutes all 6 capsules were open, after 6 minutes the shell was disintegrated and finally after 15 minutes completely dissolved. The fill was fine dispersed in the disintegration medium.

Dispersibility: The dispersibility of the fill was tested in the Paddle dissolution apparatus at 100 rpm (test medium: 0.1N HCl) within performance of the dissolution profile. After 5-10 minutes the capsule shell was opened, after 20 minutes the fill was dissolved. After 45 minutes only small particles remain in the turbid dissolution medium.

f) Capsule dimensions: The dimensions of 50 dried capsules were determined. The following results were obtained:

-   -   length: min. 20.45 mm, max. 20.89 mm, mean value: 20.71 mm     -   diameter: min. 9.96 mm, max. 10.06 mm, mean value: 9.94 mm

After 6 weeks storage at 30° C. and 40° C. all capsules were intact and the seam quality corresponded to the requirements. Due to decrease of hardness at 40° C. the capsules tended to stick slightly together. After 2 weeks at 40° C., the hardness decreased about 3-4 N/20 sec., which is typical for soft gelatin capsules at this storage temperature. Up to 6 weeks an increase of the hardness about 1-1.5 N/20 sec. was observed. This increase of the hardness is due to migration of Glycerol from the shell into the fill.

Inventive Example 84

A Macrogol formulation with Xanthan having the following composition was prepared:

mg/capsule Macrogol 600 Ph. Eur. NF 554.020 Caprylocaproyl Macrogolglyceride 175.000 Colloidal anhydrous Silica 40.000 Glycerol Ph. Eur., USP 47.000 Purified water Ph. Eur., USP 12.500 Xanthan Ph. Eur. 5.000 Tapentadol HCl 116.480 Fill weight 950.000 Density: 1.152 Volume: 13.36 minims Capsule shape: 13 oblong —Visual homogeneity up to 7 days storage:

The white suspension was homogeneous and flowable after preparation. After 1, 2 and 7 days storage a slight sedimentation was observed. After stirring and re-homogenization a homogeneous and flowable fill suspension was resulting. This fill suspension should be stored under stirring until starting of encapsulation process. If this is not possible a rehomogenization is necessary. The fill will be stirred during the encapsulation process too (routinely for all fill suspensions).

—Flowability: Strength after 10 s to 19 s: 2.72. The data comply with the specification and prove the food flowability.

—Viscosity:

The viscosity decreases slightly from 840 mPas after 1 day to 793.9 mPas after 7 days storage. All results are within the specified limits (500-2000 mPas). The data prove the physical stability and suitability of the fill formulation for the encapsulation process.

The properties of the capsules were further investigated:

Within manufacturing process of the capsules, the following parameters were tested.

-   -   Determination of IPC fill weight at the encapsulation step     -   Drying profile with overdrying for 7 days     -   Migration profile of Glycerol during manufacturing, drying and         overdrying

The dried capsules were tested regarding the following parameters:

-   -   Appearance     -   Seam thickness     -   Fill and shell weight     -   Mechanical stability     -   Disintegration     -   Capsule dimensions.

Within the temperature challenge test the capsules were stored for 6 weeks at 30° C. and 40° C. with testing of appearance, hardness and stickiness for every 2 weeks. Additionally glycerol content of fill and shell will be tested after 6 weeks storage.

Results of investigations on dried capsules:

a) Appearance: The specification of 13 oblong capsules with a pink capsule shell containing a white fill suspension was met. b) Viscosity of the fill: The viscosity of the fill mass after preparation of the fill mass was 1384 mPas. The viscosity complies with the viscosity of the fill of Pseudoephedrin Capsules, but is slightly lower than the data of the fill lab sample (1601 mPas). Nevertheless the data comply with the specification (500-2000 mPas) that is suitable for encapsulation. c) Seam thickness: The seam thickness (13/1000 inch for upper seam, 14/1000 inch for lower seam) of the dried capsules is widely above the specified limits (min. 4/1000 inch) and prove the physical stability of the selected formulation. d) Fill and shell weight: Total fill and shell weight of 20 dried capsules were determined. The standard deviation of fill weight of 6.4% of shell weight is 7.2% The shell weight complies weight the shell weight documented in the Formula Certificate. The average fill weight (1025.6 mg) is increased about 9.1% due to migration of water from fill to shell (release with water content 8.2%). e) Disintegration and dispersibility of the fill

Disintegration: The capsules were open within 3 minutes, after 6 minutes the shell was disintegrated and dissolved after 5 minutes with fine dispersion of the fill. The fill dispersibility was additionally tested with the dissolution profile.

Dispersibility: The dispersibility of the fill was tested in the Paddle dissolution apparatus at 100 rpm (test medium: 0.1N HCl) within performance of the dissolution profile. After 5-10 minutes the capsule shell was opened, after 20 minutes the fill was dissolved. After 45 minutes only small particles remain in the turbid dissolution medium.

f) Capsule dimensions: The dimensions of 50 dried capsules were determined. The following results were obtained:

-   -   length: min. 20.22 mm, max. 20.58 mm, mean value: 20.43 mm     -   diameter: min. 9.86 mm, max. 10.02 mm, mean value: 9.93 mm

After 6 weeks storage at 30° C. and 40° C. all capsules were intact and the seam quality corresponded to the requirements. Due to decrease of hardness at 40° C. the capsules tended to stick slightly together. After 2 weeks at 40° C., the hardness decreased about 3-4 N/20 sec., which is typical for soft gelatin capsules at this storage temperature. Up to 6 weeks an increase of the hardness about 1-1.5 N/20 sec. was observed. This increase of the hardness is due to migration of Glycerol from the shell into the fill. This effect is observed too at 30° C. storage. After initial decrease (2 weeks) of hardness about 1-1.5 N/20 sec., the hardness increases in the same range up to 6 weeks storage. This phenomenon is typical for soft gelatin capsules containing amphiphilic or hydrophilic fill masses based on Macrogol.

The results prove the physical stability of the formulation.

Results of dissolution profile and syringability testing: The two critical parameters to evaluate the success of the formulation development and manufacture of both pilot batches of Tapentadol 100 mg capsules are:

-   -   immediate release dissolution         -   80% after 30 minutes         -   dissolution profile in 0.1 NHCl comparable with Tapentadol             100 mg tablets     -   syringability (TRF test):         -   not more than 33% detectable in syringe after boiling of the             capsule fill with 5 ml water in order to meet the             requirements on abuse resistance of the formulation

Dissolution rate after 30 minutes, 75 rpm, 0.1N HCl Syringability Inventive 104.5% 6.8% (n = 6) Example 83 (n = 6, RSD = 1.9%) (7.8; 3.8; 1.9; 5.2; 11.0; 10.9%) Inventive 103.1% 3.9% (n = 6) Example 84 (n = 6, RSD = 1.3%) (5.9; 1.6; 3.7; 2.6; 1.1; 8.7%)

Therefore both capsules fully comply with the requirements and objectives for development and of an immediate release abuse resistant softgel formulation.

The remaining residue of the fill mass after boiling in the syringe with water was maximum 1 ml.

The specified minimum 80% Tapentadol HCl were released from the amphiphilic fill suspension after 15 minutes. After 25 minutes 100% of the active substance were detected in the dissolution medium. 

1. A tamper resistant pharmaceutical capsule comprising a capsule filling and a capsule shell, wherein said capsule filling is encapsulated by said capsule shell and comprises: (a) Tapentadol or a physiologically acceptable salt thereof in an amount within the range of from 10 mg to 400 mg, as equivalent weight relative to Tapentadol free base; and (b) a liquid excipient blend comprising a solvent, a surfactant, and a viscosity enhancer; wherein the capsule provides immediate release of Tapentadol or the physiologically acceptable salt thereof upon oral administration.
 2. The capsule according to claim 1, wherein a mixture of 250 milligrams of the liquid excipient blend with 5 milliliters of water at the mixture's boiling point forms a viscous phase which cannot pass through a 25 millimeter needle having an inner diameter of 0.60 millimeters.
 3. The capsule according to claim 1, wherein the viscosity enhancer comprises colloidal anhydrous silica and/or a gum.
 4. The capsule according to claim 3, wherein the gum is selected from the group consisting of acacia, agar, tragacanth, guar gum, xanthan gum, locust bean gum, tara gum, karaya, gellan gum, welan gum, and rhamsan gum.
 5. The capsule according to claim 1, wherein the total content of viscosity enhancer is within the range of from 0.1 to 10 wt.-%, relative to the total weight of the capsule filling.
 6. The capsule according to claim 1, wherein the total content of solvent is within the range of from 10 to 90 wt.-%, relative to the total weight of the capsule filling.
 7. The capsule according to claim 1, wherein the liquid excipient blend comprises an ion exchange resin.
 8. The capsule according to claim 7, wherein the ion exchange resin is anionic.
 9. The capsule according to claim 1, wherein the total content of ion exchange resin is within the range of from 0.1 to 25 wt.-%, relative to the total weight of the capsule filling.
 10. The capsule according to claim 1, wherein the surfactant is nonionic.
 11. The capsule according to claim 10, wherein the nonionic surfactant is selected from the group consisting of glycerol monoesters with C₆₋₁₈-fatty acids, glycerol diesters with identical or different C₆₋₁₈-fatty acids, glycerol triesters with identical or different C₆₋₁₈-fatty acids, polyethylene glycol monoesters with C₆₋₁₈-fatty acids, polyethylene glycol diesters with identical or different C₆₋₁₈-fatty acids, and mixtures of any of the foregoing.
 12. The capsule according to claim 1, wherein the total content of surfactant is within the range of from 0.1 to 35 wt.-%, relative to the total weight of the capsule filling.
 13. The capsule according to claim 1, wherein the total content of Tapentadol or physiologically acceptable salt thereof, as equivalent weight relative to Tapentadol free base, is within the range of from 0.1 to 25 wt.-%, relative to the total weight of the capsule filling.
 14. A method for treating pain in a patient in need of such treatment, said method comprising administering to said patient at least one capsule according to claim
 1. 15. A method for preventing parenteral abuse of Tapentadol or a physiologically acceptable salt thereof, said method comprising providing the Tapentadol or a physiologically acceptable salt thereof in the form of a capsule according to claim
 1. 